What does ifc coordinate 0 mean as shown in the pictures What is the coordinate system for the reader that we have to add? Do we add ll84 or x-y M?

The coordinate system here is a XY local coordinate system centered on the lat long position. ​The coordinate system is automatically detected and defined when reading the data. You can't specify the coordinate system here to choose.

The lat long position is usually taken from the ifcSite feature​

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